In the automotive industry, it may be desirable provide an anti-theft feature by locking the steering shaft of a vehicle to prevent rotation of the steering shaft when the vehicle ignition is off and the key is removed. Known systems utilize a keyed ignition system incorporated into the steering column. When the key is removed from the ignition, a mechanical steering shaft lock mechanism incorporated into the ignition switch may be actuated to lock the steering shaft in place. Other vehicles utilize a keyless system or a system where the keyed ignition system is not associated with steering column. For these configurations, an actuator that is not mechanically part of an ignition switch may be used to lock and unlock the steering shaft.
In one known steering shaft lock actuator, a locking member may be moved by the actuator from an unlocked to a locked position. When in the locked position, the locking member may engage a recess in the steering shaft to lock the steering shaft. The recess may be formed by adjacent teeth/splines of a toothed/splined ring that may be coupled to the steering shaft. An obstruction, e.g., a tooth of the toothed ring, may be encountered as the actuator attempts to drive the locking member to the locked position. The actuator motor may remain energized so that the motor drives the locking member to the locked position when the obstruction is removed. This can stress the motor and lead to early failure of the actuator. Actuator failure may be manifested in a failure of to lock the steering shaft when the vehicle is not in use and/or inadvertent locking of the steering shaft during normal driving conditions, which, of course, may pose a critical safety hazard.
Separately, it may be desirable that safeguards be provided to ensure that the steering shaft is never locked inadvertently, e.g. when the vehicle is moving. It may be further desirable, that an actuator configured for locking the steering shaft be configured to prevent facile removal when in the locked condition to provide anti-theft protection.
A system and method is needed that provides one or more of these features in a simple, reliable and/or cost-effective manner.
Although the following Detailed Description will proceed with reference being made to illustrative embodiments, many alternatives, modifications, and variations thereof will be apparent to those skilled in the art. Accordingly, it is intended that the claimed subject matter be viewed broadly.